swoboda



A. .R. SWOBO'EQA.

RHEOSTAL; APPLICATION FILED Did- 6, 1920.

Patented Nov. 21, 19 22 .2 SHEETS-SHEET 2.

by a

mentor. 1951006000 Ado/ Patented Nov. 21, 1922.

UNITED STATES 1,436,212 PATENT or fice.

ADOLPH R. SWOBODA, OF NEWARK, NEW JERSEY, ASSIGNORTOWESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

Application filed December c, 1920. Serial No. 428,540.

To all whom it may concern:

Be it known that I, ADoLPH a citizen of the United States, residing at Newark, in the county of Essex, State of New Jerse have invented certain new and useful Improvements in Rheostats, of which the following is a full, clear, concise, and

exact description.

This invention relates to cal regulating apparatussuch as rheostats and potentiometers and more particularly it relates to a rheostat designed to meet special and extraordinary requirements.

The object of the invention is the provision of a rheostat which is economical to manufacture, reliable in operation and ac cessible for the establishment of connections under difiicult conditions as will be set forth.

The embodiment of the invention described hereinafter is a rheostat intended for use in a testing set wherein there are a considerable number of pieces of apparatus mounted closely together. The rheostat is required to be both directly and remotely op' erable. The provision for remote control involves connecting a large number of conductors to the rheostat and the connections must be made after the rheostat is installed in the testing set.

The making of a large number of soldered connections in a crowded position is at best a;

difiicult undertaking, but in the present instance the difiiculty has been reduced very appreciably by means of an adjustably mounted terminal block on which the necessary terminals are mounted. After the rheostat has been installed in the testing set together with the other pieces of apparatus, the terminal block may be adjusted so that the ends of the terminals present themselves to the best advantage possible under the existing conditions. This adjustable terminal block constitutes one feature of the invention.

Another feature is a tiny resistance element comprising a coreless winding of insulated resistance wire formed into an elongated unit and bound together. By virtue of this small element the rheostat may be made very compact. The element is also very cheap to manufacture.

Other features of the invention will be apparent as:the detailed description pro-- gresses.

R. SwoBooA,"

variable electri drawing Figs. 1 and 2 are cross-sectional .views of the rheostat, Fig. 1 being taken along the line 1-1 of Fig. 2 and the latter along the line- 2-2 of Fig. 1.. Fig.3 is a diagram of a portion of a circuit in: which the present rheostat may be advantageously employed. Figs. 4 and 5 are enlarged views of one of the small resistance elements. The

, tween succeeding contacts 8 are the tiny resistance elements 10 which lie flat'against the mounting plate .4 or 5,, as the case may be, and securedthereto by an application of shellac, These resistance elements are illustrated in Figs. 4; and 5 and consist ofvery small corelesswindings of high resistance insulated wire. A lead 11 of fairly heavy gaugestranded copper wire is soldered to each end of the winding and a sleeve 12 of varnished tubing or other comparatively stiff material is slipped over the leads. These sleeves not only act as insulation for the copper leads, but they serve as reinforcing members for the element. The element is formed into an elongated unit of substan- Shaft 14 is journaled in bushings 15 and 16 and is rotatable by means of the handle 17. Insulatively mounted on shaft 14, and in engagement with the two arcuate rows of fixed contacts 8 are two contact arms 18 and 19. Fixed contact brushes 20 areeach electrically connected to one of the contact arms-18 or 19 and are provided with soldering terminals 20 for attachment to incoming leads.

A terminal block 21 is clamped to the bushing 15. By screws 22, the terminal block may be rotated through an angle of about 90. A number loosening the clamping of soldering terminals 23 are mounted on the 1.10

terminal block and flexible leads 24; are connected between terminals 23 and fixed contacts 8. The flexible leads 24 are, of course, made long enough to permit turning the terminal block.

Mounting plates 4 and 5 are joined by bolts 25 which pass through tubular spacers comprising parts 26 and 27. The mounting members 3 are provided with apertures for bolts 25 and are held between parts 26 and 27. A tail piece 3 integral with mounting member 3 engages an aperture 1 in mounting plate 4 and is thereby prevented from turning. By this arrangement bolts 25 are put to a double use and no additional parts are required for attaching mounting members 3 to the rheostat.

It is sometimes necessary to control the rheostat from a remote point and the circuit diagrai'n Fig. 3 illustrates how this may be done. There are shown parts of two main circuits, the first of which comprises conductor 30, variable resistance 31, contact arm .18 and conductor 32. The other main circuit comprises conductor 30, variable resistance 31, contact arm 19 and Conductor 32. Arms 18 and 19 being operable simultaneously, variations of the resistance of the two circuits are always substantially equal, assuming, of course, that resistances 31 and 31 are equal. To decrease the resistance of the main circuit, the contact arms 18 and- 19 are rotated in a clockwise direction and counter-clockwise to increase.

For the purpose of controlling the resistancefrom a remote point, relays 33, 33, 33 38 etc., art provided. With the contact arms 18 and 19 in their extreme positions wherein the resistances 31 and 31 are en tirely in circuit, energization of one or more relays 83, 33, etc, will short circuit part or all of the resistance elements as desired. Upon the energization of relay 33, for instance, armature 34 will close its contact and short circuit the first element of resistance 31. Armature 35 will close its contact and short circuit the first element of resistance 81'. Relays 83, 33 etc, will likewise upon energization, short circuit succeeding elements of both resistances. It will be understood that the relays may be operated from any desired point.

What is claimed is:

1. In a rheostat, a mounting plate, an arcuate row of contacts on said mounting plate, a shaft extending through said plate, a terminal block rotatably mounted on said shaft, terminals on said terminal block, and conductors connecting said terminals with said contacts.

2. In a rheostat, a pair of mounting plates, an arcuate row of contacts on each of said mounting plates, a shaft extendthrongh said plates, a terminal block rotatably mounted on. said shaft between said plates, terminals on said terminal block, and conductors connecting said terminals with said contacts.

i 3. In a rheostat, a mounting plate, an arcuate row of fixed contacts on said mounting plate, a bushing extending through said mounting plate, a shaft journaled in said bushing, a terminal block rotatably mounted on said bushing, terminals on said terminal block and conductors connecting said terminals with said fixed contacts.

4%. In a rheostat, an arcuate row of fixed contacts, a bushing concentric with said are- .uate row of contacts, a common support for said fixed contacts and said bushing, a shaft journaled in said bushing, a contact member for cooperating with said fixed contacts rotatable by said shaft, a terminal block rotatably mounted on and normally clamped to said bushing, terminals on said terminal block and flexible conductors between said terminals and said fixed contacts.

5. In a rheostat, a pair of mounting plates arranged in parallel superimposed relation, a plurality of spacers extending between said plates and situated at points near the periphery thereof, each of said spacers comprising two tubular parts, a plurality of mounting members one associated with each spacer, said mountingmembers each being secured between the two tubular parts of the spacer with which it is associated and held therein by means of a bolt which passes through apertures in said plat-es and through said spacers, said mounting members being adapted for attaching the device to a panel.

6. In a rheostat, a mounting plate, an arcuate row of contacts on said mounting plate, a resistance element associated with each contact, means for adhesively mounting said elements on said mounting plate, a shaft extending through said mounting plate, a terminal block rotatably mounted on said shaft, terminals on said terminal block, and conductors connecting said terminals with said contacts 7. In a rheostat, an arcuate row of fixed contacts, a bushing concentric with saidarcuate row of cont-acts, a common support for said fixed contacts and said bushing, a shaft journaled in said bushing, a. contact member for cooperating with said fixed contacts rotatable by, said shaft, a terminal block rotatably mounted on and normally clamped to said bushing, terminals on said block, flexible conductors between said terminals and said fixed contacts, fiat resistance elements associated with said fixed contacts, and adhesive means for mounting said elements on said, common support.

In witness whereof, I hereunto subscribe my name this 29th day of November A. 1)., 1920.

ADOLPH R. SWOBODA- 

